Stimuli-responsive delivery nanosystems: A versatile technological platform

Several studies have demonstrated the potential use of nanocapsules to improve efficacy/toxicity profile of drugs. In particular, for dermatological applications, they offer many advantages including controlled and sustained... [ view full abstract ]

Several studies have demonstrated the potential use of nanocapsules to improve efficacy/toxicity profile of drugs. In particular, for dermatological applications, they offer many advantages including controlled and sustained release of active ingredients (AI) and protection of the encapsulated AI from its environmental degradation. All these features lead to an improvement of bioavailability and therefore, improving its biological effectiveness. Stimuli-responsive polymer nanocapsules (PNCs) are smart nanocarriers that encapsulate active ingredients and release them on demand upon external triggers. Stimuli-responsive PNCs are of interest because the AI can be released via different stimuli avoiding unwanted and unspecific release.

Different biodegradable core-shell nanocapsules containing different AI were synthesized and studied for their potential as drug-delivery systems for dermatological applications. The core of these drug delivery systems consists of a polyester polyester polymer which is at the front line of attention because of their attractive safety profile. Since their degradation products are easily metabolized by the Krebs cycle and therefore easily eliminated. On the other hand, the shell was added via layer by layer assembly of different polymer electrolytes. Dynamic light scattering and zeta potential measurements were used to analyze the layer by layer assembly process and microscopy analysis to determine the thickness of the layer. These polyelectrolytes (shell) confer control over the AI release specifically in the presence of proteases (slowing down the degradation process). Therefore, the release studies were performed in different media: Different behavior was observed when the release was done in conditioned medium from Human Dermal Fibroblast (HDF), indicating that AI release exhibits a protease dependent behavior. A combination of analytical techniques was used to monitor the AI release.

In conclusion, a set of stimuli responsive safe and biodegradable core-shell nanocapsules have been developed and these nanosystems provide a versatile technological platform for topical applications.